Treating of cellulosic fiber-containing material to impart flame-retardancy thereto

ABSTRACT

MATERIALS SUCH AS CELLULOSIC TEXTILE MATERIALS ARE MADE FLAME-RETARDANT BY TREATING THEM WITH COMPOUNDS CONTAINING METHYLOL GROUPS, NITROGEN AND PHOSPHORUS. TYPICAL SUCH COMPOUNDS HAVE AT LEAST ONE RADICAL OF THE FORMULA:   &gt;N-CH2-P(=O)(-O-R5)2   WHEREIN R5 IS LOWER ALKYL. TYPICAL SUCH COMPOUNDS ALSO HAVE &gt; NH GROUPS AND/OR AMINOMETHYLOL GROUPS OF THE FORMULA &gt; NCH2OH.

United States Patent O TREATING OF @ELLIJLOSIC FIBER-CONTAINING MATERIAL T lll/IPARZI MAivIE-RETARDANCY THERETO Ronald Swidler and William A. Sanderson, Pasadena, Jose I. Garnarra, La Palma, and William A. Mueller, Pasadena, Calif., assignors to (Cotton, Incorporated, Memphis, Tenn. No Drawing. Filed June 12, 1969., Ser. No. 832,817

Int. Cl. Dtldm 13/28; 09k 3/28 US. Cl. 8-183 MI Claims ABSTRACT OF THE DISCLOSURE Materials such as cellulosic textile materials are made flame-retardant by treating them with compounds containing methylol groups, nitrogen and phosphorus. Typical such compounds have at least one radical of the formula:

wherein R is lower alkyl. Typical such compounds also have NH groups and/or aminomethylol groups of the formula NCH OI-I.

BACKGROUND OF THE INVENTION In recent years many technological advances have been made in textile technology towards providing fabrics of improved properties such as crease-resistance and flameretardancy. A wide variety of flame-retardants have been disclosed, among which are those containing nitrogen and phosphorus. Unfortunately, these prior flame-retardants suffer from a number of disadvantages. Many of these flame retardants are not compatible with conventional crease proofing agents. Others decompose at the temperatures normally employed to fix the crease proofing agents to the fabric to be treated. Still others impart initial flameretardancy but are ineffective after repeated laundering. Some impart efiicient fiarne-retardancy but adversely affect other properties of the treated material such as tear resistance, tensile strength, hand, color and susceptibility to scorching. Yet others are ineffective when employed with textiles containing cellulosic fibers such as cotton.

Accordingly, it is an object of the present invention to provide treating agents which are substantially free of one or more of the disadvantages of prior agents.

Another object is to provide flame-retardants and/or flame-proofing agents which are compatible with commonly employed crease-proofing agents.

A further object is to provide flame-retardants which do not decompose at the temperatures commonly employed to fix known crease-proofing agents.

A still further object is to provide flame-retardants which are effective after multiple laundering.

Yet another object is to provide flame-retardants which have minimal adverse effect on the treated material in terms of its tear resistance, tensile strength, hand, color and/or susceptibility to scorching.

Still another object is to provide phosphorus and nitrogen containing compounds which contain reactive methylol groups and which can be fixed on cellulosic materials singularly or simultaneously with conventional creaseproofing agents.

Still another object is to provide novel methods for treating fabrics to render them flame-retardant and creaseresistant, and novel fabric treating baths.

Still another object is to provide novel treated fabrics.

Additional objects and advantages of the present invention will be apparent to those skilled in the art by reference to the following detailed description thereof.

ice

DESCRIPTION OF INVENTION It has now been discovered that a certain class of compounds containing phosphorus and nitrogen are especially effective as flame-retardants for fibrous materials in general and for cellulosic or cotton fiber containing materials in particular.

NOVEL COMPOUNDS A typical class of such compounds are those of Formula I:

wherein R is a divalent radicat of Formula II, III, IV or V:

(I N X L (III) NX NX asset- (IV) NX O anal- (V) r i R I L-Rfl wherein R is hydrogen or a monovalent radical of Formula VI or VII:

with the proviso that at least one R is a radical of Formula VI and at least one R is hydrogen or a radical of Formula VII; wherein X is hydrogen or cyano; R and R are independently selected from the group consisting of hydrogen and lower alkyl and R is lower alkyl. The lower alkyl radicals R R and R can be substituted with one to three substituents, examples of which include the halogens such as chloro and bromo or lower alkoxy, but are preferably unsubstituted.

Compounds of Formula I wherein R is a radical of Formula V have special characteristics in that they imp part a crisp hand to the treated material whereas compounds of Formula I wherein -R is a radical of one of the other formulae impart a soft hand and are not subject to the light sensitivity frequently characteristic of the compounds when \R is a radical of Formula V.

The compounds of Formula I are synthesized by coreacting certain polyamines, certain polyalkyl phosphites and certain carbonyl compounds.

The polyamines useful to produce the compounds of Formula I are those of Formula VIII:

wherein R has the above described meaning. Examples of suitable compounds of Formula VIII include among others melamine, guanidine, guanyl urea, biguanide, and cyauoguanidine. Inorganic acid salts of the compound of Formula I such as guanidinium carbonate and guanidinium chloride can also be employed. The guanidines are preferred because of their high nitrogen to carbon ratio, their reactivity, availability and cost.

The polyalkyl phosphites useful in the present invention are those which are coreactive with polyamines and carbonyl compounds. They are generally dior tri-lower alkyl esters of phosphorus acid and are preferably those of Formula IX.

wherein R has the above defined meaning, n=0 or 1; m==2 or 3 and n+m=3. Examples of suitable compounds of Formula IX include among others tris(2-chloroethyl) phosphite, bis (2-bromoethyl)phosphite, triethyl phosphite, trimethyl phosphite, methylethyl phosphite, dibutyl phosphite, di-isopropyl phosphite, diethyl phosphite and dimethyl phosphite. The latter is especially preferred because of the minimum amount of carbon which this compound introduces into the fibrous material or textile.

The carbonyl compounds which are useful in the present invention are those which have heretofore been used in phosphonomethylation reactions such as described in Fields 118. Pat. 2,635,112, and are generally those of Formula X:

wherein R and R have the above described meanings. Classes of suitable carbonyl compounds include lower alkyl aldehydes and lower alkyl ketones, examples of which include among other acetone, methyl ethyl ketone, glyoxal, butyraldehyde, acetaldehyde and formaldehyde (HCI-IO). Any source of formaldehyde can be employed in the present invention, but paraformaldehyde and Formalin, the widely available 37 weight percent aqueous solution of HCHO are preferred because of cost, availability and reactivity. Alternate sources of formaldehyde include paraformaldehyde, gaseous formaldehyde, hexamethylene tetramine and methylal.

The reaction can be conducted neat, i.e. in the complete absence of solvents or in the presence of solvents up to infinite dilution. Examples of suitable solvents include among others, water, lower alkanols such as methanol, ethanol and butanol.

As is well known in the art, the reactivity of compounds of Formula I containing methylol groups can be reduced by capping the methylol groups with lower alkanols such as methanol or n-butanol. The capping can be conducted in situ by the use of the lower alkanol as all or a portion of the solvent or can be conducted as a separate later step.

The amino hydrogens of the polyamine undergo two reactions, a phosphonomethylation reaction according to Equation 1 and an alkylolation reaction according to Equation 2.

(Equation 1) (amino (carbonyl (polyalkyl hydrogen) compound) phosphite) (lower (water) alkanol) polyalkyl phosphite to amino hydrogen must be less than 1:1 in order to provide some unreacted amino hydrogen.

This unreacted amino hydrogen can remain as such or can be alkylolated according to Equation 2. The molar ratio of the carbonyl compound to the polyalkyl phosphite is preferably at least 1:1 in order to react all the polyalkyl phosphite.

The reaction can be conducted at widely varying temperatures from below 20 C. to above 200 C. but generally within this range and preferably between 60 and C. Either subatmospheric or superatmospheric pressures can be employed but atmospheric pressure is preferred for convenience.

In order to produce phosphonomethylated compounds containing amino methylol groups NCH OH) at least a portion of the carbonyl compound must be formaldehyde and the equivalent ratio of total carbonyl compound to polyalkyl phosphite must be greater than 1:1 in order to provide some free formaldehyde to react according to Equation 2.

NOVEL BATHS According to another aspect of the percent invention there are provided novel material treating baths. These baths can be synthesized by either dissolution of compounds of Formula I or by in situ coreaction of certain reactants.

To form the bath the compounds of Formula I can be dissolved in any solvent but are preferably dissolved in Water at any convenient concentration that will provide the treated system with a sufficiently high add-on. For instance the compound of Formula I can comprise from 0.01 weight percent up to the point of saturation, generally from 10 to 70% and preferably from 20 to 60% based on the combined weight of compound and solvent. Naturally compounds of Formula I are suitable whether produced by the above-described process or any other.

According to a preferred embodiment the bath is formed in situ by coreaction of a polyamine, a polyalkyl phosphite and a carbonyl compound at least a portion of which is formaldehyde. In certain cases the bath will naturally contain compounds of Formula I but it will also contain the reaction products of certain competing reactions which surprisingly and unexpectedly do not adversely affect the crease-resistance and the fire-retardance of treated materials.

The term polyamine as used herein refers to nonpolymeric compounds having a molecular weight of 20 to 300 and preferably 30 to 150, having at least one but preferably a plurality of amino nitrogen atoms each of which has at least one amino hydrogen. The preferred polyamines have at least two NH groups and have an atomic ratio of nitrogen to carbon of at least 1:1 and preferably at least 2:1. The polyamines of Formula VIII are the preferred polyamines because of their high nitrogen to carbon ratios and the resistance to laundering exhibited by their compounds. Examples of other suitable polyamines include among others diurea, thiourea, glycoluril, melamine, methlyamine, ethylene diamine as well as polyamines of 'Formulae X1 through XIV:

(XII) HO-CH-CH-OH III) O (XIV) The reactants can be employed in widely varying ratios but in order to produce a bath that will produce fire-retardant fibrous materials resistant to laundering the reactants must be present in certain critical ratios. For example when the polyamine is one of Formula VIII then the molar ratio of carbonyl compound to polyamine is broadly 1:1 to 10:1 and is preferably 3:1 to 5:1 and the molar ratio of polyalkyl phosphite to polyamine is broadly 0.5:1 to 4:1 and preferably 1.5:1 to 2.5:1. When operating outside the above broad ratios the fire-retardant character of the treated material disappears after one or two launderings whereas within the preferred ratios it is possible to produce treated materials which retain their flame retardant character even after fifty launderings. Adjustments in the above ratios will be readily apparent to those skilled in the art when practicing the present invention with polyamines having greater or lesser number of reactive amino hydrogens, or with polyfunctional polyalkyl phosphites or polyfunctional carbonyl compounds.

According to a preferred embodiment of the present invention the bath further comprises a nitrogen-containing cross-linkable crease-proofing agent and preferably one containing amino methylol groups which are coreactive with amino hydrogens and/or amino methylol groups on the compounds of Formula I and/ or on the reaction products of the reactants of the bath and with the hydroxyl groups of cellulose.

Examples of suitable such crease-proofing agents include among others methylolated ureas, methylolated melamines, dimethyloldihydroxy ethylene urea which is commercially available as Permafresh 183, and tetramethylol glycoluril. Tetramethylol glycoluril is preferred because it gives good addons and is durable to laundering. Methylolated melamines are also very good and have the advantage of imparting a crisp hand to the treated materials. They are especially useful where light stability is not a problem.

The crease-proofing agent is preferably present in the bath such that the molar ratio of nitrogen to phosphorus in the bath and one the material is 1:1 to :1.

TREATING THE FIBROUS MATERIAL The fibrous material is contacted with the bath by any convenient means such as by spraying the bath on the material or immersing the material in the bath. The excess bath liquid is then removed from the fibrous material by any convenient means such as passing the material through the nip of two rotating rubber rollers. The material is then dried preferably under mild conditions to avoid premature curing and preferably at 20 to 100 C. Finally, when the fibrous material is in the shape desired of the intended end product, it is then heated to a temperature above 100 C. and below the degradation temperature of the material and preferably at 120 to 180 C. to fix the applied compound or compounds on the material. The drying and heating steps can be conducted simultaneously but are preferably conducted sequentially.

The treated fabric preferably has sufficient add-on such that it exhibits the desired degree of flame-retardancy and crease-resistance. Materials generally have addons of 1 to 40 and preferably 10 to 30 percent.

GENERAL CONSIDERATIONS The process is applicable to a wide variety of fibrous materials and especially cellulosie fibrous materials containing cotton or viscose fibers, e.g., fibers, filaments, yarns, threads, and particularly woven and non-Woven fabrics. It is especially useful in the manufacture of permanentpress garments, but offers important advantages in the manufacture of other types of cellulosic textile articles as well, whenever good shape retention and fire-retardance are desired, e.g., in the manufacture of tufted cotton carpets, molded cotton batting and so forth. The invention is particularly effective with natural cellulose materials such as cotton and linen but is also applicable to regenerated cellulose such as viscose and high wet modulus (polynoisc) rayon. The invention is also useful for fabric blends containing minor amounts of cellulosic fiber, e.g., blends of cotton and polyester (such as polyethylene terephthalate), cotton-and-nylon, etc.

The term lower as used herein with lower alkyl, lower alkoxy and the like refers to a carbon atom content of one to four. The term add-on as used herein refers to the Weight increase due to adhesion of solids from the bath based on the original weight of untreated material. Thus a g. sample of cotton cloth dipped in a bath, dried, cured, washed, dried and conditioned at 65% relative humidity at 70 F. nd then found to weigh g. would be said to have a 25% add-on.

The invention is further illustrated by the following examples in which all parts and percentages are by weight unless otherwise indicated. These non-limiting examples are illustrative of certain embodiments and are designed to teach those skilled in the art how to practice the invention and to represent the best mode presently known for carrying out the invention. In the following examples treated materials are tested for flame resistance according to AATCC34-1966 and for crease-resistance according to ATTCC 66-1959T which gives wrinkle recovery angles. Where indicated the laundering is performed in a home-type washing machine using a low-suds detergent.

Example I Item Ingredient Percent A Amlno-phosphite condensate 35 B Catalyst e.g., H P0 or NH Cl 0. 5 C a. Additive e.g., tetrarnethylolgylcoluril. 10 D Triton X-ltlO-nonionie wetting agent 0. 25 E Mykon SF-polyethylene fabric softener 3 The remainder is water.

Item A is dissolved in an equal weight of water and the pH adjusted to 3.5 with 50% NaOH solution. Items B, C, D, and E are then added and the pH again adjusted to 3.5.

Pad baths were prepared containing 10% of tetramethylolglycoluril and 0.5% NH Cl (Bath A) and 10% tri methylolmelamine and 0.5% NH Cl (Bath B) and the results of their application to twill are shown in Table 1.

7 8 TABLE 1 Example IV wRA 2 This example illustrates the synthesis of compounds of Add Flame degree the present invention from guanidinium hydrochloride,

-on retardt percent mm 1 Dry Wei: 5 cyanoguamdme, d1methyl phosph1te and formaldehyde 1n aqueous solution. 1 20-25 287 216 1% 2?) 50 20 212 The followmg quant1t1es of the followmg 1ngred1ents i.e., The number of washes before the sample burns 4% in the flam are combined as mdlcated:

2 Wrinkle recovery angle.

Quantity of- Example II Gram This example illustrates the use of trimethylphosphite Item Ingredient Grams 1110195 and dimethyl phosphite. A Guamdirfiugnhydrochlonde 57.3 0.0 c 'd'n 16 s g 02 mole) B i'fitfiiifi fint it? 1"? yanoguam 1 e Guanidinium chloride 19.2 g. 0.2 mole). D Fmahn 3-ZHCHO Paraformaldeh de 24.0 g. (0.8 mole). Dimethyl hosghite 66.0 g. (0.6 mole). Items A and B are j fi Item Q at ,IOOIII g Trimethyl phosphite 24.8 (02 mole). ture to form a react1on mixture which 1s then rapldly heated to 90 C. and cooled. Item D 1s added and heated to The {above l'eact?nts, Wlth F exceptlon of the dlmethyl 20 reflux over a period of 10 minutes and maintained at a PhosPhlte, were mlxedfind Stirred at room t m q reflux temperature of 78-100 C. for an additional 5 0 ml. of methanol bemg added to make stirring eas1er. minutes to give a clear pale yellow Solution After half an hour, an exotherm developed with some effervescence. The mixture was stirred for an additional Example V half and then the dimethyl phosphite added and the 25 This example illustrates the synthesis of compounds of solution reflux d f 2 HI the present invention and fabric treating baths employing Pafafol'maldehyde l was then added, such compounds produced from guanidinium carbonate, plus 50 m1. methanol and the solution refluxed for one cyanoguanidine, dimethyl phosphite and formaldehyde hour- The Solutlon WaS @VaP0Tated under reduced P The following quantities of the following ingredients sure to give a clear, v1scous liquid which was used to r mbined a indicated: prepare pad baths as previously described. Bath A10% tetramethylolglycoluril+0.5 g. NH C1 Quantity Bath B10% trimethylolmelamine+0.5 g. NH Cl G TABLE 2 Item Ingredient Grams male?- WRA z A-.. Guanidinium carbonate 54 0.3 F] d 1 B Cyanoguamdine 16.8 0.2 Addml 3 agree 0.- Dimethylphosphite 170 1.6 Bath percent ance 1 Dry Wet D Forma'hn 260 2 ECHO A 20 35-40 269 202 40 B 20 193 220 Items A, B, and C are mixed and heated rapidly to 85 12 s footnotes 1 Ebottom of Table C. over a period of 10 minutes and then allowed to cool E 1 HI to 50 C. whereupon a clear pale yellow liquid results. To Xamp e this liquid is added Item D dropwise over a 25 minute This example illustrates the synthesis of a bath of the period. The temperature increases due to exothermic represent invention employing guanidinium carbonate, diaction to a maximum of 73 C. and then reduces to 43 methyl phosphite and formaldehyde in aqueous solution. C. at the end of the period of addition of Item D. The The following quantitities of the following ingredients temperature of the reaction mixture is then raised to are combined as indicated: 95 C. and heated at 95-100 C. over a period of 40 minutes. Quantity of- Example VI Grem- Pad baths were prepared as in Example I, except that Item Ingredwnt Grams moles the reaction products were not evaporated and an amount A Guanidinium carbonate 18 of the aqueous solution was taken so as to give 35% of n1 1 11 hit 66 0.0 E p e [15130110 the amino-phosph1te condensate 1n the pad bath. The results are shown in Table 3.

TABLE 3 Flame WRA, degree Addon, retard--- Example Additive Catalyst percent ant Dry Wet Items A and B are heated rapidly to 90 C. until A Example VII dissolves in B forming a solution which is then allowed to cool to 70 C. whereupon the solution is rapidly cooled with Dry Ice to 25 C. Item C is then added dropwise to the solution over a 7 minute period during which the temperature of the reaction mixture rises to 68 C. and then drops to 60 C. The temperature of the reaction mixture is then raised to C. over a 15 minute period and maintained at 80 to C. for a period of one hour.

This example illustrates reaction of two polyamines, formaldehyde and dimethyl phosphite in the absence of Reactants mixed and stirred under nitrogen in an oil bath at 120 C. When the reaction temperature reached 100" C. an exotherm developed and the flask was removed from the oil bath. When the exotherm subsided, the flask was returned to the oil bath and heated at 100 C. for 30 minutes. Then paraformaldehyde (9.0 g.; 0.30 mole) and methanol (15 ml.) were added and the solution heated under reflux for 2 hours. The solution was cooled, diluted with 50 ml. H and its pH adjusted from 1.4 to 3.5 with 7 ml. of 50% NaOI-I. Teteramethylol glycoluril (16.0 g.), NH CI (0.8 g.), Triton X-100 (0.4 g.) were then added and the solution diluted to 160 g. with water to form a bath.

The bath was padded onto twill, dried for 15 minutes at 88 C. and cured for 15 minutes at 160 C. The resultant fabric was flame-retardant for over 20 washes.

Example VIII Six equivalents of formaldehyde 18 g.) and one equivalent of melamine (12.6 g.) were dissolved in hot water (IO-80 C., 100 ml.) at pH 10, three equivalents of dimethyl phosphite (33 g.) were added as soon as a color less homogeneous solution was obtained, and the resultant solution was rapidly cooled in ice water. Treatment of cotton twill or printcloth with a 40% solids bath of this reaction product, using no added catalyst, afforded fabric which was fire resistant for more than twenty home-type launderings. The fabric had durable press properties, with dry and wet crease recovery angles of 250275.

Example IX Six equivalents of formaldehyde (18 g.) and one equivalent of melamine (12.6) were dissolved in water at 70- 80" (100 ml.) at pH 10, and 3 equivalents (85.8 g.) of tris- (Z-chloroethyl) phosphite were added as soon as a homogeneous solution was obtained, and the resultant solution was rapidly cooled in ice water. Fabrics were padded with a solution containing 60% by weight of these reactants to a wet pick-up of 70% for twill and 100% for printcloth. The resultant fabrics were dried and cured in the manner previously described and had add-ons of 22% and 33% respectively. These fabrics were flame retardant for over 15 home launderings and had dry crease recoveries of 269 and 205 respectively.

Example X Cyanoguanidine (16.8 g.), dimethyl phosphite (44 g.) and formaldehyde (24 g.) were combined in water and heated at 80-100 C. for one hour. The resulting solution was cooled, adjusted to pH 3.5, 0.5% phosphoric acid was added as catalyst, as well as 0.25 Triton X-100 wetting agent, 3% Mykon SF polyethylene emulsion, and 5% Resloom HP crosslinking additive to form a material treating bath. Total solids concentration was 40%. Gotton twill was padded to 80% wet pickup, dried and cured, after which it was flame retardant for greater than 12 washes.

Example XI Guanidinium carbonate, dimethyl phosphite and formaldehyde in mol ratios at 1:2:4 were dissolved in water and heated at 80-100 for one hour. Baths were made up as described in Example XIII with the exception that the final pH of the solution was 5.0. Fabrics treated with this bath had 15.1% ad-on after 1 wash, had a soft hand, dry crease recovery of 300 and wet crease recovery of 259, and flame retardance durable for at least 14 washes.

Example XII Biguanidine (10.1 g.) was methylolated with two equivalents of paraformaldehyde (66 g.) by refluxing in solvent methanol (150 ml.) for 40 minutes. Two equivalents of dimethyl phosphite (22 g.) were then added, and the mixture refluxed for one hour. Two additional equivalents of paraformaldehyde (6.6 g.) were then added, and rei0 fluxed until homogeneous. The solvent was removed, and a 35% solids aqueous pad bath was made up containing 0.5% ammonium chloride as catalyst and 10% tetrarnethylol glycoluril as additive. When treated as described in Example XIII, the resultant fabric had a crisp hand, dry and wet crease recovery angles of 292 and 267 C. respectively, and was flame retardant for over 15 washes.

Example XIII Guanylurea (31 g.) in methanol (50 ml.) was stirred for 30 minutes with paraformaldehyde (18.8 g.). Dimethyl phosphite (69 g.) was then added causing an exothermic reaction. The solution was refluxed for 30 minutes, then the pH was adjusted to 8-9 with sodium hydroxide and the solution stirred for 1 hour with Formalin (formaldehyde content 28.2 g.). This solution was used to prepare a pad bath in the usual way using 10% of tetramethylolglycoluril as additive. The finish applied to twill gave a very soft hand at 16.4% add-on and the char length after I wash was 3 /2".

Example XIV Guanidinium chloride (9.6 g.; 0.1 mole), dimethyl phosphite (22 g.; 0.2 mole) and methylal g.; large excess) were refluxed for one hour without apparent change. Methanol (50 ml.) and concentrated hydrochloric acid (2 ml.) were added and the mixture refluxed for 30 minutes, after which time the reaction mixture was clear and homogeneous. The methanol and methylal were removed under reduced pressure and cotton twill was treated with a pad bath containing 35% by weight of this product, 10% tetramethylol glycoluril, and 0.5% ammonium chloride catalyst. The fabric had soft hand, good wrinkle resistance, and was flame retardant for more than 15 washes.

Example XV Example XVI Reactants:

Cyanoguanidine 16.4 g. (0.2 mole). Paraformaldehyde 12.0 g. (0.4 mole). Trimethyl phosphite 49.6 g. (0.4 mole).

Dimethyl phosphite 4.4 g. (0.04 mole).

The reactants were mixed and stirred under nitrogen in an oil bath at C. A vigorous exotherm developed as the reaction mixture reached 95 C., and the flask was removed from the oil bath. When the reaction had subsided, the reaction mixture was heated at 90 C. for 2 hours. Then paraformaldehyde (12.0 g.; 0.4 mole) and methanol (30 ml.) were added, and the solution heated under reflux for 1 /2 hours. The methanol was removed on a rotary evaporator and the resultant viscous liquid dissolved in water (50 ml.) and its pH adjusted from 4.6 to 3.5 with a few drops of phosphoric acid. A pad path was prepared containing 32% of this material, 9% tetramethylol glycoluril, 0.5% NH Cl and 0.25% Triton X- 100. The fabric was dipped in this material and then dried for 15 minutes at 85 C. and cured for 15 minutes at C. The fabric had an add-on of 13.5% after 1 wash and in the flame test burned 4". The flame retardance had gone after 10 Washes.

Example XVII Cyanamide (21 g. of 50% solution; 0.25 mole) and dimethyl phosphite (27.5 g.; 0.25 mole) were mixed, paraformaldehyde (15 g.; 0.5 mole) was added, and the mixture was stirred and heated at 80 C. until clear (1 hour). Water was added to bring the solution to 40% solids, the pH was adjusted to 3.5, and 0.5% Triton X-lOO and tetramethylol glycoluril were added. Cotton twill was padded, dried, and cured in the usual way and had an add-on of 19.7% after 1 wash, and was flame resistant for 4 washes.

Example XVIII A mixture of guanidinium chloride (38.2 g.), cyanoguanidine (16.8 g.), dimethyl phosphite (132 g.) and formaldehyde (195 g.; 37%) were dissolved in water and heated 2 hours at 80l00 C.

Pad baths were made up from this reaction product as in Example XXIII, and a number of cross-linking addi tives compared, as illustrated in the following table:

A pad bath was prepared as in Example XVIII using 10% tetramethylol glycoluril as additive. A sample of rayon jaquard drapery was treated with this bath in the manner described previously and was found to be flame resistant for at least home-type launderings.

Example XX Thiourea (7.6 g.) and 37% aqueous Formalin (32.4 g.) were mixed, dimethyl phosphite (22 g.) was added, and the resulting solution was heated at 8590 C. for 45 minutes and allowed to stand at room temperature for 16 hours. The pH was adjusted to 3.5 with 50% sodium hydroxide, tetramethylol glycoluril (10 g.) was added, as was 0.25% Triton X-100. The mixture was diluted to a total of 100 g. with water, whereupon a small amount of solid separated from the solution. A sample of cotton twill was padded to 80% wet pickup, dried 15 minutes at 90 C., cured 15 minutes at 160 C, and washed in a home type washing machine on the normal cycle using concentrated detergent. The resulting fabric gave a 4 inch char when tested in the standard flame test.

Example XXI Urea was methylolated with two equivalents of formaldehyde and the resultant dimethylolurea was suspended in one equivalent each of dimethyl phosphite and trimethyl phosphite. The mixture was heated slowly to 85 C. whereupon solution occurred. The solution was heated at 85 C. for 24 hours, cooled, and one equivalent of 37% aqueous Formalin was added and the solution stirred for one hour. A pad bath was made up from this product as described in Example XXVI, and a sample of treated fabric, after washing, was flame resistant for two washes.

Example XXII This example illustrates the maximum durability of flame-retardancy when the reactants are present in the preferred molar ratios.

Pad baths were prepared as described in Example I except that the proportions of the reactants were varied as indicated.

12' TABLE (1) Mol ratio of gua.: DMP'zHCHO:

(2) No. of washes before loss of flame retardance 1:124 0 1:1:5 0

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described above and as defined in the appended claims.

What is claimed is:

1. A method of rendering cellulosic fiber-containing materials flame-retardant comprising in sequence the steps of:

(I) contacting the material with a compound of the formula:

wherein R is a member selected from the group consisting of wherein the R s are selected from the group consisting of hydrogen, radicals of the formula:

and those of the formula:

with the proviso that at least one R is a radical of the Formula A and at least one R is hydrogen or a radical of the Formula B; wherein X is hydrogen or cyano; R and R are independently selected from the group consisting of hydrogen and lower alkyl and R is lower alkyl;

(II) heating the material to fix the compound on the material.

2. The method of claim 1 wherein R is 13 M 3. The method of claim 2 wherein R3 and R1: are References Cited hydrogen UNITED STATES PATENTS thdfl' lfuth om"ng: 4 The f r er c 2,828,228 3/1958 Glade et a1 117-136 (III) drYmg the mama? at to 190 and 3,160,515 12/1964 Goldstein et a1 8-116 P (IV) heating the material to 120 to C. 5

5. The method of claim 4 wherein the cellulosic fiber- LEON ROSDOL Pnmary Examlner containing textile material prior to heating to 120 to 180 WOLMANa Assistant Examiner C. is contacted with an aqueous solution of at least one crosslinking and crease-proofing agent selected from the 10 US Cl. X.R. group consisting of methylolated ureas, methylolated melamines, dimethylol dihydroxy ethylene urea and tetra- 8 116 192 MP methylol glycoluril. 

